Search strategies for top partners in composite Higgs models

Abstract

We consider how best to search for top partners in generic composite Higgs models. We begin by classifying the possible group representations carried by top partners in models with and without a custodial SU(2) × SU(2) Z 2 symmetry protecting the rate for Z → bb decays. We identify a number of minimal models whose top partners only have electric charges of 3 and thus decay to top or bottom quarks via a single Higgs or electroweak gauge boson. We develop an inclusive search for these based on a top veto, which we find to be more effective than existing searches. Less minimal models feature light states that can be sought in final states with like-sign leptons and so we find that 2 straightforward LHC searches give a reasonable coverage of the gamut of composite Higgs models.

Top partners searches and composite Higgs models

“…16 A few theoretical analyses are however present in the literature. They mostly focus on single decay channels, namely T → Zt [78,79], T → ht [80,81] and T → W b [82][83][84], with the exception of ref. [85] which considers a combination of T → W b and T → ht.…”

LHC top partner searches beyond the 2 TeV mass region

“…For other studies involving hadronic final state see refs. [6,7,[12][13][14]. We provide a strategy and a detailed phenomenological study which shows that in preferred regions of pNGB composite Higgs models one can discover top partners (at 5 sigma CL) with mass as high as 2 TeV at the 14 TeV LHC run, and with integrated luminosity of roughly 35 fb −1 .…”

“…The lower p T cut on the fat jet allows for some low fat jet p T events to migrate into the sample which passes the Basic Cuts due to the fact that we use a large R = 1.0 cone for fat jet clustering. 13 Furthermore, the effects of pileup on any observable constructed out of the r = 0.4 jets are limited (compared to the fat jet) by the small jet cone size, but can still be non-negligible at 50 average pileup events.…”

“…For the convenience of the reader, we however give the explicit values g R XW t and g R BW t at the model sample points we used in the captions of figures 10-12 and the corresponding cut-flow tables. 13 Note that, in principle, the effects of pileup can further be suppressed by lowering the size of the fat jet cone without increasing the lower pT cut on the fat jet. Figure 10.…”

XQCAT: eXtra Quark Combined Analysis Tool

“…Such new top partners can naturally exist near the EW scale without upsetting the existing measurements, and are often crucial to cure the divergences in the Higgs mass corrections in scenarios going beyond the Standard Model (BSM). Notable examples involve models with composite Higgs states [1][2][3][4][5][6][7][8][9]. They also appear as manifestations of extended symmetries in models of Little Higgs [10,11] and in Grand Unified scenarios [12,13] or as excitation modes of the SM quarks in theories with extra dimensions [14][15][16][17].…”